1. Field of the Invention
This invention relates to a keyboard input device forming integrally therein a pointing device which controls the position of a cursor or the like.
2. Description of the Related Art
In a desktop type personal computer, in general, a pointing device such as mouse is placed separately from a keyboard input device requiring, therefore, a space dedicated to the pointing device and, hence, requiring a wide space for installing the desktop type personal computer.
Therefore, there has been proposed a keyboard input device by integrally mounting a pointing device on a support plate on which a plurality of key switches are mounted.
In such an integral pointing device, a cylindrical operation body is erected on a central portion of a plate-like base and a plurality of distortion sensors are mounted surrounding the operation body.
Further, a support plate having a plurality of key switches mounted on the front surface thereof is provided with a plurality of cylindrical mounting rods erected downward on the back surface thereof. The base of the pointing device is mounted on the lower ends of the mounting rods while permitting the operation body to penetrate through to the surface side of the support plate.
On one surface of the base, there are arranged a plurality of distortion sensors capable of detecting distortion of the base. When the base undergoes the distortion due to the operation for tilting the operation body, the distortion is detected by the distortion sensors. Desired coordinates can, then, be input being corresponded to the amounts of distortion detected by the distortion sensors.
The above keyboard input device integral with the pointing device offers such advantages that a decreased area of installation is required and that the device can be easily carried, and is, hence, finding increasing demands in a field where decreasing the size is essential as represented by portable personal computers.
In the pointing device of the above keyboard input device, however, the base is mounted on the mounting rods erected downward from the support plate forming a gap between the support plate and the base.
Therefore, if the operator accidentally spills water droplets or the like liquid on the support plate during use, then, the water droplets fail on various electronic parts arranged under the base infiltrating through the gap causing the quality of the electronic parts to deteriorated.
Besides, the pointing device has the distortion sensors arranged on one surface of the plate-like base. Therefore, when the operation body is tilted, the portions of the base mounting the neighboring distortion sensors interfere with each other, making it difficult to highly precisely detect the direction in which the operation body is tilted or the amount of tilt, arousing a problem of decrease in the sensitivity of the distortion sensors.